Method of producing stainless-clad steel plate



Feb. 22, 1966' D. H. HUBBLE ETAL 3,

TIL E5.- 1..

DAV/0 H. HUBBLE and EUGENE IV. SILVER/VAN W Attorney United States Patent 3,235,936 METHOD OF PRODUCING STAINLESS-GLAD STEEL PLATE David H. Hubble, Pitcairn Borough, Pa., and Eugene N.

3,235,936 Patented Feb. 22, 1966 metal-to-metal contact and thus welding of the adjacent surfaces to provide for easy separation of the stainless steel plates upon cooling. In addition, the steel plates contract to a greater extent than the glass during cooling Silverman, Youngstown, Ohio, assignors to U.S. Steel 5 to breiak any bond that may have formed between the Company, a corporation of Delaware materials when they were at elevated temperatures.

Filed June 21, 1963, Ser. No. 289,602 As shown in FIGURES 1 and 2 of the drawing, a sheet 4 C i (C 29-19) of glass 2 is disposed between a pair of stainless plates 4 of suitable thickness, such members formed into a core The present invention relates to the production of car- 6 by joining the edges of the stainless steel plates by weld bon steel plate clad with stainless steel and more parmetal 8. Thereafter the core may be disposed in an ticularly to an improved method for providing such clad ingot mold 10 and carbon steel 12 cast therearound. plate from a composite ingot which is readily separable Many glass compositions are suitable for use with the after rolling. method of our invention. It is preferred, however, that As described in the Ingersoll Patent No. 1,868,749, an 15 the viscosity of the glass be such that its temperature economical method for producing stainless-clad plates softening point (temperature at which the glass flows includes the steps of joining two stainless-steel plates under its own weight) is lower than the temperature of having a separating medium therebetween by welding the ingot during the final rolling pass. Hence, the temalong their edges. The resulting sandwich assembly is perature softening point should be lower than the lowest then positioned vertically in the center of an ingot mold, temperature encountered during hot rolling. It is also and carbon steel is cast around it to form a composite preferred that the viscosity of the glass be such that it ingot having the sandwich assembly extending vertically will not become excessively fluid at the maximum temthrough the center thereof. The mold is then stripped perature encountered during hot rolling. Excessive flufrom the ingot, and the ingot is hot rolled to the desired idity makes confinement of the glass in a sandwich conthickness- The Product is sheared into P which are struction difiicult and gives rise to a possible reaction of then side sheared to remove the welded areas at the edges. the glass with the stainless steel. The temperatures en- The plates will then separate along the area of their cross countered during hot rolling are usually between 1500 section comprising the separating-medium layer to form d 2450 F the desired stainlessjclad Steel p The thermal expansion of the glass should be appre- Mammals Qonventlonally used the Para/[mg medlum ciably different from that of the steel to insure easy sepmc1ud ?a1um1f1a (A1203), magneslum M aration upon cooling. Generally, glass that exhibits chromlum. oxlde (Cr2O3)' h are apphed elther thermal expansion sufficiently lower than steel has a high Slurry or m y fOTm to pmvlde a bye}- Of the matena SiO content and low NaO and K 0 contents. between the ad acent surfaces of the stainless steel plates. M H b1 I f th b Since the medium is not continuous it separates as the t commefcla y aval a g1 asse.s Sa 18 y e a Oveingot elongates during hot rolling of the composite ingot mentioned requirements. The following are examples of to 16 ave areas of meta1 to metal Contact betwem the two widely different glasses that have a thermal expansion jacent surfaces of the stainless steel plates. Such areas of 10 to 3X10 6 P degl'ee t t0 tend to weld together during the hot rolling and thus suband have been used Successfully Wlth the method of 0111 sequent separation thereof is difficult if not impossible. 40 invention:

Chemical Composition, Percent Glass S102 A1203 N320 K20 \MgO 0&0 B80 F0203 B203 Window Glass 72.3 1.9 13.5 0.5 0.2 10.6 0.6 0.0 0.1 Pyrex 80.5 2.2 3.8 0.4 *ND ND ND ND 12.9

*NDNot determined.

Accordingly, it is an object of our invention to provide a method for producing a composite ingot that may be easily separated into stainless-clad plates after hot rolling.

A more particular object of our invention is to modify the conventional method of producing composite ingots by providing a separating-medium layer that during hot rolling elongates with the ingot and thus remains continuous to provide for easy separation upon cooling.

The foregoing and further objects will be apparent from the following specification when read in conjunction with the attached drawing wherein:

FIGURE 1 is an enlarged elevational view partly broken away of a core assembly embodying our invention; and

FIGURE 2 is a sectional view of an ingot mold embodying the core assembly of FIGURE 1.

We accomplish these objects by using a glass plate as the separating medium to replace the granular materials conventionally used for this purpose. During hot rolling, the glass increases in area with the steel and thus provides a continuous separating layer between the adjacent surfaces of the stainless steel plates. This prevents The most likely commercial glass would be a common soda-lime-silica glass (Na O-CaO-SiO in the range of 0 to Na O, 0 to 50% CaO, and 30 to 70% SiO Glasses of this type are preferred because of their low cost and availability.

The initial thickness of the glass separating layer should be varied according to the final thickness to which the ingot is reduced during hot rolling. For example, if 0.003 inch of separating glass is desired in a final rolled product reduced to 0.050 of its original thickness, the original thickness of the glass separating layer should be 20 0.003 or 0.060 inch. The final thickness of the separating layer may be varied from 0.001 to 0.20 inch, with a 0.001- to 0.0l0-incl1 thickness being preferred.

A specific example of the practice of our invention is as follows: A piece of window glass A; by 9% by 14 /8 inches was placed between two by 10 by 15-inch type 304 stainless steel plates. The three sections were joined in a sandwich assembly by welding along the edges of the stainless steel plates. The sandwich assembly was placed vertically in a 5- by 12- by 17-inch ingot mold, and 300 pounds of carbon steel were cast around it.

After stripping the mold, the ingot was heated to 2300 F. and rolled from the original 5-inch thickness to a 2-inch slab. It was then cut into two pieces. The cut edges of each piece were welded to prevent the escape of glass during subsequent rolling, and the pieces were heated to 2300 F. One piece was then rolled to a final gage of /2 inch and the other to /8 inch. The rolled pieces were side sheared to remove the welded areas at their edges. Upon cooling, complete separation of both pieces was achieved. The surface of the stainless cladding was bright and smooth indicating that the glass had no detrimental effect on the stainless steel.

While we have shown and described several specific embodiments of our invention, it will be understood that these embodiments are merely for the purpose of illustration and description and that various other forms may be devised within the scope of our invention, as defined in the appended claims.

We claim:

1. The method of making stainless steel clad steel plate comprising separating a pair of stainless steel plates with a plate of glass, joining the edges of the stainless steel plates by a weldment, placing carbon steel backing plates in contact with the stainless steel plates and rolling said assembly to weld the stainless steel to the carbon steel, the glass plate preventing welding together of the stainless steel plates.

2. The method of forming a composite metallic plate comprising forming a core of juxtaposed metal plates with a plate of glass therebetween, joining by weldment the adjacent edges of said juxtaposed plates, placing said core in a mold and casting metal therearound to form a composite ingot and hot rolling said ingot to formcomposite metallic plates, the plate of glass maintaining the juxtaposed plates separate and preventing welding of the 0pposed surfaces thereof during hot rolling of said ingot.

3. A composite for forming bimetallic plates comprising a pair of juxtaposed metal plates, a plate of glass therebetween, the adjacent edges of said metal plates being joined together by weldment to maintain the glass plate between said metal plates during rolling therof.

4-. A composite for forming bimetallic plates comprising a pair of jnxtaposd metal plates, a plate of glass therebetween, the adjacent edges of said metal plates being joined together by a weldment to maintain the glass plate between the metal plates, and cast metal around said pair of juxtaposed plates adapted to be welded thereby by rolling of said composite.

References Cited by the Examiner UNITED STATES PATENTS 7 2,041,255 5/1936 Marburg 29-19 3,066,384 12/1962 Heger 29-19 RICHARD H. EANES, JR., Primary Examiner. 

1. THE METHOD OF MAKING STAINLESS STEEL CLAD STEEL PLATE COMPRISING SEPARATING A PAIR STAINLESS STEEL PLATES WITH A PLATE OF GLASS, JOINING THE EDGES, OF THE STAINLESS STEEL PLATES BY A WELDMENT, PLACING CARBON STEEL BACKING PLATES IN CONTACT WITH THE STAINLESS STEEL PLATES AND ROLLING SAID ASSEMBLY TO WELD THE STAINLESS STEEL TO THE CARBON STEEL, THE GLASS PLATE PREVENTING WELDING TOGETHER OF THE STAINLESS STEEL PLATE. 